Even if the Democrats hold the Senate, the dynamic there will change for the worse if their Republican counterparts are more Trumpist—more conspiracy-minded, more jingoistic, more convinced that the people on the other side of the aisle are godless, evil, amoral socialists. Such a caucus would be even more likely to engage in reckless acts of obstruction and conflict. The effect would almost certainly be more exaggerated in the House, where the Marjorie Taylor Greene contingent will likely grow. As the average level of extremism in Congress rises, it becomes harder to tell true believers from opportunists. The former President, banished from Twitter, can appear marginalized, yet the G.O.P. is heading into the midterms with Trump as its leader.

Earlier this year, when Trump began talking about handing out endorsements, Mitch McConnell, the Senate Minority Leader, said that he would push back if he thought that Trump’s choices would cost the G.O.P. seats. Last month, though, McConnell told Politico, “I don’t believe they’re troubling.” (The exception appears to be in Alaska, where Trump’s effort to bring down Lisa Murkowski hasn’t gained traction.) McConnell was seemingly content with Brooks, and with Trump’s endorsement of Herschel Walker, the former football player with a tumultuous business and personal life who has promoted election-fraud conspiracy theories and will challenge Warnock, in Georgia. “There’s every indication he’s going to be a good candidate,” McConnell said. Whether he would be a good senator didn’t seem to matter.